AUDI Q3 – AFS CALIBRATION (ECU 55) AND 09/A5 ALIGNMENT AFTER OBD11: TECHNICAL GUIDE 2025
Updated 08/20/2025 • Practical guide to resolve the Adaptive Light error after coding with OBDeleven or equivalent tools.
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🛒 Buy now on Amazon✅ Introduction: When AFS calibration is needed and why after coding
On Audi Q3s with adaptive headlights/AFS, the Adaptive Light warning light or system unavailable messages may appear after coding or activation (e.g. Light Assist ). In most cases, it is sufficient to perform the Basic Settings of control unit 55 – Headlight Range and check the consistency of modules 09 – BCM and A5 – Front Sensor Driver Assist . This guide takes you step-by-step , with operational checklists and workshop advice.
Read Also: AUDI Q3 – ADAPTIVE LIGHT FAULTY AFTER OBD11/OBDELEVEN: CAUSES, DIAGNOSIS, SOLUTIONS (2025)
🧰 Prerequisites and security
- Stabilized power supply (12 V charger/maintainer) during diagnosis and Basic Settings.
- Long Coding Backup and Adaptation of 09 / A5 / 55 modules (OBDeleven: “Backup”/“History” function).
- Flat area , standard setup, correct tire pressures , normal vehicle load.
- Tools: OBDeleven Pro (or equivalent), optional headlight leveling kit , and aiming wall/screen.
🔎 Initial diagnosis
1) DTC reading and freeze-frame
- Scan 09 – Cent. electric , A5 – Front Sensor , 55 – Headlight Range .
- Note DTCs , freeze-frame conditions, and counts (how many times the error occurred).
2) Check hardware and configuration
- Check axle level sensors and headlight connectors (rust, fasteners, pulled cables).
- Check presence and status of windshield camera (if Light Assist/ADAS present).
- Check PR-codes (luggage compartment or logistics label) to confirm headlight/AFS equipment fitted.
🛠️ AFS calibration in 55 – Headlight Range (Basic Settings)
The procedure may vary slightly depending on the year/month of the vehicle and the diagnostic tool. Typical sequence:
- Open module 55 – Headlight Range → Basic Settings .
- Perform Initialization/Reset adjustments (reset positions).
- Select the Headlight Adjustment/Aiming function:
- Move the headlights to the adjustable position (usually automatic down movement).
- Mechanically adjusts horizontal/vertical according to specifications and projection screen.
- Confirm learning and save the new home position.
- Perform lock-to-lock steering (lock-to-lock steering) if required.
- Clear DTCs in module 55 and restart the dashboard .
🔄 Alignment 09 – BCM and A5 – Front Sensor Driver Assist
Minimum consistency checks
- 09 – BCM : Verify that bits/bytes related to headlights, level sensors and AFS are consistent with the actual equipment.
- A5 – Front Sensor (if present): check calibration status (OK/Required). If the camera is out of calibration, perform the procedure with the control panel; alternatively, contact an ADAS center.
- Make sure 09 ↔ 55 ↔ A5 communicate on the CAN (no DTC “missing message”).
🧪 Road test and validation
- With illuminated area and wall, check light cut and adaptive movement when steering.
- If Light Assist is active: night test on extra-urban roads, speed > 40 km/h, rain/light sensor clean.
- Reread the modules after the test: no pending DTCs, no incrementing counts .
🧩 Typical errors and quick fixes
- “AFS calibration missing” / “Headlight adjustment not performed” → repeat Basic Settings in 55, check trim/pressures.
- “Missing CAN messages 09↔A5↔55” → check wiring/connectors, consistent coding in 09, no blocking gateways.
- “Camera not calibrated / position not learned” (A5) → calibration procedure with official target; if not available, ADAS center.
- Basic Settings not available → low voltage, DTCs active, requirements not met (doors closed, steering wheel centered, normal load).
🛡 Prevention (workshop best practices)
- One change at a time and immediate verification (test + status backup).
- Working notes : Record bytes/bits touched and the reasoning; keep screenshots.
- Quick Recovery : Always keep an original profile to get back to stock.
- Battery maintenance : during encoding and Basic Settings use maintainer .
Read Also: A5 CAMERA CALIBRATION AND LIGHT ASSIST AFTER WINDSHIELD REPLACEMENT (AUDI Q3)
❓ FAQ – Frequently Asked Questions
Can I activate automatic high beam (Light Assist) without AFS?
It depends on the setup. If the appropriate camera and headlights are missing, software activation isn't enough and may cause errors. Always check the PR codes and existing hardware.
After coding the Adaptive Light indicator reappears: what do I check first?
1) DTC in 09/A5/55 • 2) Battery voltage • 3) Level sensors connected • 4) Repeat Basic Settings in 55 with regular setup.
Do you need steering alignment (G85) for AFS?
Not always, but if steering angle errors appear or the AFS does not follow the curve, run the G85 Basic Setting and the lock-to-lock cycle.
Can I do the AFS calibration in the garage?
Yes, if you have a wall/screen, flat space, and the manufacturer's procedures. A5 camera calibrations require specific equipment: it's best to contact an ADAS center.
